Firstly, does anyone know a good method of removing and old O2 sensor. I've already cut the wire and used a wimpy impact gun. I tried that when it was fairly hot (the exhaust that is). No go.

Also, someone mentioned before about testing the cat by banging on it and listening to see if it rattles. I did that and there are at a few pieces rattling at the cat inlet. Replace it? I'm pretty sure you'll say yes.

When I replace the cat, does it have to be welded back on, or can I just clamp it?

 

Factory cats are bolt-in's. You can buy a replacement bolt-in "high-flow" cat for less then a factory replacement cat. Most cats you'll find at local parts stores are "universal" cats, meaning, either weld it in, or spend an extra $15-$20 for their bolt-in kit. Makes no sense, might as well just go aftermarket high-flow.

As to removing the oxy sensor, I always bust off the pigtail like you did, and use a "real" socket on a 15 inch breaker bar. If that fails, use a box-end wrench (not the open end), and hit the wrench with a hammer (simulates an impact gun). If all else fails, a garage could cut/drill the old one out, and either chase the threads in the bung, or weld a new bung on. Those stupid "special oxy sensor sockets" with the slot in the side are useless- due to that slot in the side, the socket spreads itself open and can either strip the oxy sensor's nut -or- wedge itself onto the oxy sensor.

 

I paid 8 bucks for one of those cut-open sockets. Although it will help torqueing the new one on. I was thinking of drilling it out, but I don't know what problems I might run into. My car is running better without the (old) sensor hooked up.

So after-market highflows are bolt-on?

 

Spraying it down with pentrating lub while its hot can help it get into the threads. Think I did that a few times till it came lose.

Changing the fuel filter is worse.

Matt

 

The replacement cat I got from AZ was like $65 w/lifetime warranty , it just clamps right in, no kit needed.

 

Awesome. I might try again to get the sensor out, or I might just take it to a shop. I didn't have a problem with my fuel filter though. The cat will be replaced, and hopefully that will improve things considerably.